1. Field of the Invention
The present invention relates to disc players that are suitable for playing, for example, optical compact discs (CDs) and, more particularly, to control systems for disc players.
2. Description of Related Art
Recently, in the field of audio equipment, digital audio disc playback systems utilizing pulse code modulation (PCM) technology to play back sound as faithfully as possible have been development. Of these systems, playback systems employing CDs have become especially popular.
The CD conventionally used in a digital audio disc playback system is made from a transparent resin and has a diameter of approximately 12 cm and a thickness of approximately 1.2 mm. The CD has a thin metal film deposited on at least one disc surface, and pits or depressions are formed in the thin metal film. The pits or depressions produce light reflectivities that are different from the reflectivity of the non-pitted portions of the metal film and that correspond to 1 or 0 of digitized data. When a signal is read out from a CD, the disc is rotated at a variable rotation speed between 200 and 500 rpm so that an optical pickup incorporating a semiconductor laser or photoelectric transducing device tracks the information storage area of the rotating CD with constant linear velocity while moving radially from the center portions toward the outer portions.
A CD stores such a large quantity of information that a single side can provide approximately one hour of stereophonic music. A CD is far superior to a conventional analog phonograph record in sound quality, information storage density, and applicability to sophisticated control facilities.
Conventional CD players intended, for example, for home use, however, do not possess adequate operating flexibility to satisfy the demand for sophisticated control facilities. For example, conventional CD players provide only one disc compartment with one disc playback unit so that, each time a CD is finished playing, the playback operation has to be interrupted by manually exchanging a new disc. Thus, neither continuous and sequential playback of a plurality of discs, nor selective playback of portions of a plurality of discs at will is possible with conventional CD players.
Although such features presently are finding application in multi-disc players for commerical use, for example, in jukeboxes, the techniques presently being considered are strictly for this type of use only and cannot meet the non-commercial demand for greater operating flexibility referred to above.
An object of the present invention is to provide a disc player capable of holding simultaneously a plurality of discs.
Another object of the present invention is to provide a disc player that permits continuous and sequential playback of a plurality of discs and selective playback of portions of a plurality of discs at the will of the user.
A further object of the present invention is to provide a disc player with sophisticated control facilities conveniently operable by the user.
Additional objects and advantages of the present invention will be set forth in part in the description that follows and in part will be obvious from that description or can be learned by practice of the invention. The objects and advantages of the invention can be realized and obtained by the apparatus particularly pointed out in the appended claims.